Potentiometric thick-film sensor for the determination of the neurotransmitter acetylcholine

Abstract

A potentiometric thick-film biosensor for the determination of the neurotransmitter acetylcholine is presented. The selective membranes consist of two layers. The first is a choline- and H(+)-selective membrane made from a poly(vinyl chloride)-poly(vinyl acetate) copolymer which is plasticized with 2-nitrophenyl octyl ether. It contains 1% m/m of the ion-pair choline phosphotungstate as an electroactive compound. Both products of the enzymic cleavage, choline and H+, are detected. The second layer is placed above the first and is made from a poly(vinyl acetate)-polyethylene dispersion polymer. It is loaded with 2% m/m of acetylcholinesterase isolated from electric eel. The linear region of the response curve extends from 2 x 10(-5) to 0.01 mol dm-3 in buffer solution and undiluted horse serum. The detection limit is 5 x 10(-6) mol dm-3 and the response time is about 4 min.

A Survey of Applications of Polyoxometalates

“…Eppelsheim and Hampp described a biosensor for the determination of the neurotransmitter acetylcholine. The sensor was based on a two-layer selective poly(vinyl chloride)-poly(vinyl acetate) membrane consisting of a choline phosphotungstate as the electroactive compound.…”

Ceramic-based multisite microelectrode arrays for simultaneous measures of choline and acetylcholine in CNS

“…Although excellent detection limits and selectivity can be achieved with the aforementioned methods, due to their temporal limitations, they are unable to monitor second-by-second events in vivo. AChE/choline oxidase (ChOx)-based microelectrode arrays (MEAs) implanted into brain tissues provide faster response times and finer spatial resolutions required for accurate second-by-second measurements of ACh and Ch in heterogeneous brain tissues (Burmeister et al, 2005;Karube et al, 1993;Tamiya and Karube, 1992;Navera et al, 1991;Eppelsheim and Hampp, 1994;Doretti et al, 2000;Lin et al, 2004;Mitchell, 2004;Parikh et al, 2004;Cui et al, 2001;Garguilo and Michael, 1996).…”

Stripping Voltammetric Determination of Choline Based on Micro-Fabricated Composite Membrane

“…14,15 Due to the growing needs for on-site clinical monitoring of the choline, enzyme modified amperometric sensors for the detection of choline using carbon microelectrode have been developed by Xin et al 16 and the design of implantable choline and acetylcholine sensors using electrochemical method have also been attempted by several authors. [17][18][19] Stripping voltammetry has frequently been used for monitoring environmental and clinical trace metals either by anodic 20 or adsorptive stripping voltammetry. 21 These methods have an excellent sensitivity and ppb levels are routinely measured for heavy metals in aqueous solutions.…”